1. Field of the Invention
The present invention relates to document processing machines and, more specifically, to a paper currency feeder mechanism for a bank note processing machine.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Typical document processing machines feature a document feed path into which a stack of documents to be processed is placed. A stripping device strips documents from the stack one at a time and passes the stripped document into a document path inlet for subsequent detection, sorting, and the like. For proper stripping operation, adequate pressure must be maintained between the stripping device and the document stack.
In a gravity-feed arrangement, the document stack is placed upon the stripper device. Initially the weight of the document stack provides sufficient pressure to allow the document stripper to function properly. However, as the document stack is depleted the weight of the document stack decreases causing a reduction in the pressure felt between the stripper and the documents. A reduction in pressure causes the stripping device to slip unless its action is slowed. Consequently, the stripping action is diminished and the document throughput is adversely affected.
In an essentially vertical feed arrangement, a feeder paddle is utilized to overcome the effects of gravity and to maintain a relatively consistent pressure between the document stack and the stripper device. In this arrangement the documents are placed upon a feeder paddle which raises the documents until the top of the stack contacts the stripper device. The stripper then removes documents one by one from the top of the stack and feeds them sequentially into the document path inlet of the processing machine for subsequent processing. As documents are stripped from the stack, the feeder paddle must raise to compensate for the decreasing height of the stack and to maintain sufficient pressure against the stripper mechanism. Thus, stripper action is relatively consistent regardless of the stack size because of the pressure exerted by the feeder paddle upon the stack.
Document throughput in a document processing device depends upon the speed at which documents can be fed into the note path. With the vertical feed arrangement the stripper action and corresponding throughput can be optimized based upon the relatively consistent pressure applied by the feeder paddle. As the document stack is processed the throughput remains optimal. However, when the stack is depleted throughput drops as another document stack is loaded into the feed path. Thus, even existing vertical document feeder devices encounter periods during which throughput is adversely affected. Accordingly, a need exists for a document feeder apparatus that allows optimal document feed pressures even during document reloading in order to optimize document throughput in the processing machine.